Mozilla has announced the availability of the first Firefox 3.1 beta release, an important development milestone for the popular open source web browser. Mozilla aims to make Firefox 3.1 a strong incremental improvement with user interface enhancements, new features, and increased support for emerging web standards. The new beta release includes a modest handful of noteworthy changes that improve the user experience.

Mozilla had originally planned to start code freeze for beta 1 in the middle of August, but decided to delay the beta release and do an additional alpha release instead.

The beta includes Mozilla's new TraceMonkey JavaScript engine, which uses tracing optimization to deliver a massive performance boost that makes it faster than Google Chrome's V8 engine. Although it still falls short of Apple's recent Squirrelfish Extreme project, the Mozilla developers say that TraceMonkey still leaves plenty of room for additional optimization.